Control mechanism for aircraft engines and superchargers



W5 H. A. ALEXANDERSON ETAL 2,495,554

CONTROL MECHANISM FOR AIRCRAFT ENGINES AND SUPERCHARGERS 7 Filed Oct. 7,1944 9 Sheets-Sheet l INVENTORS ATTORNEY Jan. 24,, WBU

Filed Oct. 7, 1944 H. A. ALEXANDERSON El AL CONTROL MECHANISM FORAIRCRAFT ENGINES AND SUPERCHARGERS 9 Sheets-Sheet 4 INVENTORSHowardflAkrozzdsrsoz BY HarOldfl.W/LeeIQr ATTUQND hm. 24,, 395% H. A.ALEXANDERSON ETAL 2,495,564

CONTROL MECHANISM FOR AIRCRAFT ENGINES AND SUPERCHARGERS 9 Sheets-Sheet5 Filed Oct. 7, 1944 Q -g@ m l INVENTORS HowardAfllexamdenson A TTU/FNEY H. A. ALEXANDERSION EI'AL 2,495,564 CONTROL MECHANISM FUR AIRCRAFTflan, 2%, W@

ENGINES AND SUPERCHARGERS 9 Sheets-Sheet 6 Filed Oct. 7, 1944 INVENTORSHoward A.Al9xmzdersozc ATTU/FNE Y Jan, 4

Filed Oct. 7, 1944 I THRO TLE EDNTRU L.

REGULATOR (")fidTROL.

INTERECIULER H. A. ALEXANDERSON ETAL CONTROL MECHANISM FOR AIRCRAFTENGINES AND SUPERCHARGERS 9 Sheets-Sheet 7 Auxl LIARY SUPEQCHAREER AIR.INLET SUPEREHARCIEE BY HaralalA.

ATTORNEY Jam. 2%, WBfi H. A. ALEXANDERSON EI'AL 2,495,564

CONTROL MECHANISM FOR AIRCRAFT ENGINES AND SUPERCHARGERS Filed Oct. '7,1944 9 Sheets-Sheet 8 uuaktuw Eooodm C 00 Q9 0 m O m 3mm WQQ U mr Q Qt40 Ezou m ojum nzuozv 195W H. A. ALEXANDERSON ET AL 2, 95,56

CONTROL MECHANISM FOR AIRCRAFT ENGINES AND SUPERCHARGERS Filed Oct. '7,1944 m 9 Sheets-Sheet 9 INVENTOR ATTORNE i ntented lion 2% race .srA'rEsPATENT OFFICE CONTRQL MECHANISM FOR AIRCRAFT Howard A. Alexanderson,

ENGINES AND SUPERCHARGERS Wood Ridge, and

Application ilctober 7, i944, Serial No. 557,672 16 Claims. (c1. 230-5)The present application pertains to improvements in the control meansdisclosed in the copending application Serial No. 550,646 of HowardAlexander-son filed August 22, 1944, now Patent No. 24153550, datedNovember 9, i948, and relates to internal combustion engine controls andmore particularly to novel regulator means for governing the airsupplied to the combustion chambers oi the engine.

An object of the invention is to provide a novel regulating device foran aircraft engine.

Another object oi the invention is to provide a novel linkagearrangement and mechanical assemhiy for a regulating device.

Another object of the invention is to provide novel means forcontrolling the operation of an exhaust driven turbine supercharger,including means for maintaining a minimum operation of the same. Incertain types of superchargers as is well known in the art the turbinedriven supercharger serves the additional function of supplying air forcooling certain portions of the turbine hearings. Thus if the operationof the supercharger be terminated, while the engine is in operation,overheating oi the portions cooled by the supercharger would result dueto the high temperatures of the exhaust gases.

Another object oi the invention is to provide novel means for regulatingthe intake pressure of an aircraft engine including means for regulatingthe operation of an exhaust driven supercharger so asto maintaindifierential pressure above atmospheric pressure regardless of theselected intake pressure, and thereby assure operation of thesupercharger during the operation of the aircraft engine.

Another object of the invention is to providea novel low boost lockoutarrangement for preventing the minimum differential control fromefiecting an increased operation of the supercharger, when the manuallyoperable pressure selecting means is positioned withina predeterminedminimum pressure range.

nnother obiect oi the inventionis. to provide in addition to theaforenoted minimum range and normal control, novel governor means forpreventing the supercharger from overspeeding.

Another object of the invention is to provide novel mechanical means forinterconnecting the several control means previously noted in a compactassemblage.

These and other objects of the invention will become apparent frominspection of the following specification when read with reference tothe ill Bit

accompanying drawings wherein is illustrated the preferred embodiment ofthe inventon. It is to be expressly understood, however, that thedrawings are for the purpose of illustration only, and are not designedas a definition of the limits of the invention, reference being had tothe appended claims for this purpose.

In the drawings, wherein like reference numerals refer to like partsthroughout the several views:

. Figure 1' is a view in elevation of one form of the invention.

Figure 2 is a sectional view taken along the lines 2-2 of Figure 1.

Figure '3 is a sectional view of Figure i taken along the line 3-3.

Figure 4 is a sectional view of Figure 2taken along the lines ii-ii.

Figure 5' is a fragmentary sectional view of Figure 1 taken along thelines 5-5.

Figure 6 is a view in elevation of the opposite side of the device fromthat shown in Figure 1.

Figure 7 is a schematic View illustrating the operating linkagearrangement of the form of the invention shown in Figure l.

Figure 8 is a schematic view illustrating the form of the inventionshown in Figure 1 applied as a supercharger regulator.

Figure 9 is a chart graphically illustrating the mode of operation ofthe invention.

Figure 10 is a schematic view illustrating the the form of the inventionshown in Figure 1 applied as a supercharger regulator and responsive tothe exhaust pressure from the aircraft engine.

Referring first to Figures 1 through 7 reference characters ii and i2designate levers having an operative connection with shafts I3 and itrespectively; the lever B I being adapted for manual operation by meansof a pilot's control lever Ila in a manner such as shown in Figure 8 andthe lever it may be operatively connected by a link lie to waste gateizbof a supercharger as shown in Figure 8.

The shaft it (and therefore the lever I2) is adapted to be swung in bothdirections to produce a corresponding shifting of the element controlledthereby in response to automatic shifting of a servo element H5. Theservo element it has provided a hub portion l1 (Figure 5) internallysplined or serrated to engage corresponding splines or serrations l8 onthe central portion of the shaft M. The servo element It is shown inFigures 5 and 7 as in the form of a vane, movable between two radialabutments 2i and 22 in reemes sure to the sector shaped chambers 23 and24 which are formed at opposite sides. of the vane II by abutments 2iand 22 on the one hand, and vane I on the other. The vane It has blades21 slidably mounted therein and forced under tension of springs 21a soas to fit snugly against the inner cylindrical surface of the housingmember 2|. Similar blades 25 mounted in the abutments 2| and 22 are.biased under tension of springs 2511 into contacting relation with hubI! so as to seal the oppositely disposed chambers 22 and 2|. The meansfor controlling the alternate supply to, and exhaust from, the chambers23 and '20 is shown as including a valve assembly consisting of acentral movable plunger portion 3i (see Figures 3 and '1) and fixedlymounted sleeve 32.

The valve assembly is housed in a central portion 28 which extendsupwardly from the main housing 59 of the device, and is located directlyabove the operating linkage connecting the manually operable shaft I3with the valve 2i. As probably best shown in Figures 3 and "1, thelatter connecting means includes a pin portion I3a provided at the innerend of the shaft honed in eccentric relation to the tion of the shaftI3.

Fulcrumed on the eccentric pin portion I 3a is a lever oil which isoperably connected at one end by linkage members 4| to one end of asecond level it. The lever 24 is connected at the opposite end bylinkage members 53 to the valve plunger ill.

The lever till is further connected through link- I 2 and posiaxis ofrotaage member 25 to an arm 61 fixedly connected to a rockshaft 35journaled in a bearing 5i, carried by the housing 35. The latter linkagearrange-.

ment is freely movable in a chamber t8 formed in the housing 39. Therockshaft 09 is adapted to receive at the opposite end an apertured endportion 52 of a lever 53 which is suitably fastened thereto. The lever53 is positioned in a second chamber 56 formed in the housing 39. Thelever 53 is operatively connected through a reciprocable element 56, toa slack diaphragm 5i and a. pressure responsive membrane, bellows ordiaphragm element 53.

The lever ld previously noted is fulcrumed on a pin I la provided at theend of a shaft Mb. The shaft Mb is connected by a key I ic to the shaftIt, as shown in Figures 4 and 7. The pin portion Ida is positioned ineccentric relation to the axis of rotation of the shaft I l and Mb.

The link Ml is so pivotally. mounted on the inner pin portion I la thatthe link 40 will swing in response to rotation of shaft It-ltb; but thepin and link M are not rigidly fastened, one to the other, as the link Mcan also be swung by movement of the link t i, even though the shaft II-J lb and inner pin portion I la of the shaft Mb are held stationary bythe balanced pressures acting upon opposite sides of vane I5.

The same is true of the connection between the inner pin portion Ida ofthe shaft I3 and the arm 50. Thus, movement may be imparted to the armto connecting links M and it by movement of the eccentric'pin portionIda and also by independent movement of links ll and it eflected throughoperation of the pressure responsive element 53.

The lever 50, as will be explained hereinafter, has an' operativelinkage connection with the outer end of a reciprocable element 55constituting part of the pressure responsive diaphragm assembly whoseflexible membrane or diaphragm element is shown at 53. The diaphragmassembly gagement. A nut 6! is also threadedly engaged with the member56 and serves to clamp the flexible diaphragm 51 to the tral portion ofthe diaphragm.- Attachedto the plate 58' at its periphery is theflexible corrugated bellows 63 whose opposite end is attached to theperiphery of a plate 64 which is secured to the end surface 56 of abellows casing tile, as indicated at 61 and 6B. The member 63 thusconstitutes a bellows adapted to be pre-evacuated, and a coiledcompression spring 1| is mounted in the bellows to urge the plate 50(and hence the'diaphragm 51) in a rightward direction as viewed inFigure 7, thereby opposing the collapsing tendency of the evacuatedbellows, and holding the latter in equilibrium. A screw 12 is providedfor limiting movement of member 56 in response to expansion of thebellows 63 under the biasing force of the spring 1|. The screw 12projects through the housing wall 39 and may be adjusted from theexterior thereof upon removal of a cap 12a;

Oil or other liquid is provided for filling the space between theelements 63 and 58, on the one hand, and the inner surface of the slackdiaphragm 51 on the other. This oil constitutes a dampening agency aswell as constituting the meansfor transmitting to the bellows 63 thepressure being supplied to the diaphragm 51 by the fluid medium in thechamber 54 as will be explained. In other words, the pressure whichopposes the spring 1| is transmitted by the slack diaphragm 51 directlyto the oilin space 95, and

same time serves to segregate the dampening liquid from the supply offluid medium which is introduced to the chamber 56.

In the present invention, as probably best shown in Figures 2, 4 and 7the arm 53 is 0p erably connected to the member 56 by means of a novellinkage arrangement. The latter arrangement includes a floating leverI20 pivotally connected at one end to the free end of the arm 53 and atthe other end to a link I2 I.-

The lever I20 has pivotally connected ata point intermediate theopposite ends thereof one end of a link I22. The link I22 is pivotallyconnected at the opposite end to a lever I23 at a point intermediate itsopposite ends. The lever I 23 has one end thereof pivoted on member I 24.which projects into chamber 54 of the housing 39.

The opposite end of the lever I23 is pivotally connected to the member56. Thus upon movement of the bellows 63 correspondin movement will beimparted to the arm 53 through the floating lever I20.

The link I2! previously described operably connects one end of thefloating lever I20 to an end of a second floating lever I26. Theopposite endof the floatin lever I26 is pivotally connected to an armI21 of a bell crank lever pivoted at I28 on a fixed pin carried by thecasing 39 and positioned therein.

The bell crank lever has also provided arms I 29 and I30. The arm I30 isoperably connected at the end thereof to one end of a spring Itl member58 at the cen-.

, lever arm lit in a counter clockwise direction,

as viewed in Figures 2 and 7 so as to bias a pin ill towards the left.The pin ill is operably connected to an overspeed governor controlindicated generally by the numeral I35.

The overspeed governor control I35 has a shaft lit, which is connectedat 136a to a drive shaft ill, as shown schematically in Figure 8,connected through suitable transmission gearing to a drive shaft ill ofa supercharger its. As is shown in Figures 8 and 10 the supercharger I39is driven by an exhaust gas turbine N of I a type well known in the artconnected through a conduit ill to the exhaust system of the aircraftengine.

The overspeed governor control llll may be of conventional structurewell known in the art including fly-balls ill operably connected to theshaft its so that upon rotation of the shaft i36 the fly-balls ill tendunder centrifugal force to be biased outward against the biasing forceof a spring ill. The fly-balls ill may be mounted at the free outer endsof arms ill, which are pivotally connected at ill to suitable projectinglugs afixed to the driven shaft I36.

The inner ends of the arms ill have slots Illt in which is engaged aradially extending pin ill. is longitudinally movable in the drivenshaft l3t. The pin l ll is likewise movable in a longitudinal slot illprovided in the driven shaft lit. The pin llll moves in the slot ill inresponse to movement of the arms l lll under centrifugal force acting onthe fly-balls ill. Thus upon move-- ment of the fly-balls llll outwardlyunder centrifugal force the pin ill is actuated through means of thearms ill and pin ill in a direction toward the right as viewed inFigures .2 and 7 biasing the arm ill in a clockwise direction againstthe biasin force of the spring iii.

A cam lid is adjust-ably amxed to the inner surface of the casing is bya screw ltd. The cam lllil limits the movement of the arm ill under thebiasing force of the spring ill.

The floating lever lit has pivotally connected thereto at a pointintermediate the opposite ends thereof one end of a link lill. Theopposite end of the link ltl is pivotally connected to a stem memberl'bl screw threadedly engaged in a cup shaped member liili having a headportion ltt. A nut member lbll is screw threadedly engaged on the outerside of the cup shaped member it? and is arranged to clamp between thehead portion ltt and a washer ltl a flexible diaphragm ltl.

The flexible diaphragm it? extends across a recess ltt provided in thecasing 39 and a recess ill formed in a cap member ill. diaphragm ltl isfastened between the cap member i ll and the casing ill. 1

A; spring ill is positioned between the cap ill and the cup shapedmember ltt biasing the cup shaped member i 55 through an opening I02extending from the recess IE5 into the chamber it formed within thecasing 39. The stem member ltl moves with the diaphragm I55 in responseto the difference in the pressures acting The pin l ll is amxed to thepin ill which at'the opposite sides of the diaphragm I 82. Atmosphericpressure is exerted upon the diaphragm I62 at the chamber I10 through aport I12 formed in the cap I", while the pressure acting upon thediaphragm I62 at the opposite side will equal the fluid pressur exertedwithin the. chamber 54, since. the fluid medium within chamber I65 isaffected thereby through passage I82.

A conduit I90 leads into the interior of the chamber 54 from the airinlet conduit I9I for the carburetor as shown in Figure 8 or as shown inFigure 10 a conduit I90a may lead into cham-.

ber 54 from the exhaust conduit I4] of the engine.

Thus the pressure in the chamber M will vary in accordance with thepressure of the air supplied the aircraft engine through thesupercharger I39, which pressure may be effected by changes in thesurrounding atmospheric pressure due to the changes in the altitude ofthe aircraft or may vary due to other operating conditions of theaircraft engine. I

It will be seen that the fluid pressure within the chamber 5i whichopposes the spring H of the bellows 63 constitutes in conjunction withsaid spring one of the operating means for the valve 3| shifting linkage56, I23, I22, I20, 53, 49, ll, l6, in, M, ii and 43. Hydraulic fluid maybe supplied the valve ll by means of a pump (not shown) operated bysuitable driving means. The

.said fluid medium under pressure is adapted to be supplied to thechambers 23 and 24 of the servo unit under control of the movableplunger ill of the valve assembly, which plunger is in turn under thecontrol of the linkages ll, it, ll, fill, ill, and it provided in thechamber 48.

The linkage it as previously indicated is operably connected to one endof the rockshaft 49, which is in turn connected at the opposite end tothe lever 53 movably mounted in the chamber 56. The lever 53 is operablyconnected .to the reciprocable member 56 and is urged in one directionby the pressure of the spring Ii upon the elements 58 and 51, and in theopposite direction by the pressure or a fiuid medium supplied to thechamber E l by way of a conduit shown at Mill in Figures 6 and 8 orconduit I90a in' Figure 10, which conduit may be connected at itsopposite end as previously indicated.

Figure '7 shows diagrammatically the manner in which the shifting of theplunger SI of the valve assembly operates to supply fluid to ,one sideor the other of the servo-motor i6 of Figure '7, while at the same timepermitting an exhaust of operating fluid from the opposite side thereof;the conduits connecting the valve chamber with the chambers 23, 2t ofthe servo unit being indicated at 9'! and 98 respectively, and thesupply conduit at 99, while the two exhaust (drain) passages areindicated at it! and I02, the former The flexible v the neutral positionso long as the waste gate setting of Figures 8 or l0'is correct formaintenance of the desired pressure in the engine intake I9I or exhaustsystem MI of the engine respectively, at the engine loading and altitudeconcurrently prevailing. When engine loading aeentoc W or altitudechanges. however, the said D will change correspondingly. If thepressure increases the pressure in chamber 58 will increasecorrespondingly, as the chamber lit is connected to one of the saidsystems as previously indicated. This pressure increase will causedisplacement of the slack diaphragm 51, and the pressure thus exertedupon the interposed liquid 95 will cause a contraction of the bellowsGit-the liquiditself being incompressible. The resulting contraction ofthe bellows B3 (axially) will cause member 58 of Figure 7 to shift tothe left, and this will cause arm 53 to turn the rockshaft ea in thebearing iii in a counter-clockwise direction. This turning will move thelinkage till, 16, M, (ii, M and 63 and hence the valve plunger ill willestablish two' parallel paths of flow; one path being from servomotorchamber 26 to the outlet it! (Figure 7). and the other path being frompressure source til to the servo-motor chamber 23. The pressure thusexerted on vane It of the servo-motor will cause rotation of the shaftIt in a counter-clockwise direction, as viewed in Figure 7, so as toeffect'through arm I2 a corresponding opening of the waste gate I2b, toeiTect a decrease in,the controlled pressure in order to restore thesame to the predetermined valve. Upon such rotation of shaft it acorresponding movement will be imparted to shaft Mb and eccentric pinMa, causing the shaft Mb and pin Ida to move in a counter-clockwisedirection as viewed in Figure 7 due to the eccentricity of the pinportion Ma of the shaft Mb in relation to the axis of rotation of theshaft Itb. Such movement of the pin Ida will cause the link M to swingon its pivotal connection to the link iii in a clockwise direction so asto tend to lower valve plunger 3i to the neutral position, whichtogether with an expansion of the diaphragm 51 to the right due todecrease in the controlled pressure will effect a return of the valvealto a neutral position. The action of the pin I ia thus tends toanticipate the change in pressure effected by the adjustment of the armI2 and provides a follow-up arrangement which gives stability to thecontrol device. When the controlled pressure drops below thepredetermined point, the bellows 53 will expand to shift member 56 tothe right as viewed in Figure 10, and the linkage will then cause valveplunger 3i to move to a lower position. Again two parallel paths of flowwill be established, but this time they will operate to swing vane it inthe opposite or clockwise direction, as viewed in Figure 7 thus shiftingthe arm I2 oppositely to the direction heretofore referred to so as toincrease the controlled pressure. The follow-up" action of the pin I iamoving in a clockwise direction will actuate link ill so as to tend toagain restore the valve 3i to a neutral position when the controlledpressure has been restored to normal.

Likewise upon manual adjustment of the lever Ii there will be imparted amovement to the cocentric inner pin portion i3a of the shaft is, whichas previously explained will cause the link iii horizontally connectingthe links 436 and iii to swing in such a manner as to pivot on itsconnection to the link 66 so as to move the linkages ti, it, t3 andhence the valve plunger 3! in a direction to effect an adjustment of thethrottle or waste gate setting. The latter movement will also efiect anadjustment of the value of the controlled pressure setting at which thebellows 51* will adjust the valve plunger M to a neutral position.

Thus it will be seen that by adiusting the lever Ii in acounter-clockwise direction asvlewed in Figure 7, the pin I3a will moveabout the axis of rotational the shaft [3 and thus the fulcrum point ofthe lever ill will beadjusted causing a clockwise movement of the lever40 about its pivotal connection to the link 36. Such'movement of the.lever Ml will impart a downward movement to the link 43 and valve 3i.Thus operation maybe effected of the arm I2 in a clockwise direction forincreasing the controlled pressure by an appropriate adjustment forexample of the waste gate I2b of Figure 8 for closing the waste gate I2bincreasing the driving speed of the supercharger.

It will be further seen that by c anging the fulcrum point of the levertil by the aforenoted adjustment of the pin I311, the determinedpressure setting to be maintained by the diaphragm 51 is increased.

Likewise the determined pressure setting to be maintained by thediaphragm El may be decreased by moving the lever II, as viewed in Figur7, so as to adjust the eccentric pin Ida in a clockwise direction aboutthe axis of rotation of the shaft I3 and thus the fulcrum point of thelever Ml so as to move the link it in a counterclockwise direction aboutits pivotal connection to the link 66.

The follow-up action of the pin ita, previously described, will ofcourse upon rotation of the shaft 5th in response to adjustment of theshaft I3 and eccentric pin I3a tend to restore the valve plunger 3i to aneutral position. The pin Na is arranged so as to have eccentricitysomewhat less than the eccentricity of the pin Ida.

If the pin I la is provided with an eccentricity too great with relationto the pin I311, the action of the eccentric pin I ia. will tend to overpower the operation of the pressure responsive diae phragm 51. Thereforein order to assure a proper follow-up action by the pin Ma, the pin I lais provided with an eccentricity somewhat less than that of the pin I3a,and preferably the eccentricity of the pin Ita is from ten to fortypercent of the eccentricity of the pin I30. depending upon the degree offollow-up desired. Further in order to assure the ready adaptability. ofthe device to varying operating conditions the housing member 28 of theservo mechanism shown in Figure 5, 12 adapted to be removed from themain housing 39, as shown in Figure 6, so that the shaft I ib and itseccentric pin I ia may be removed and a shaft I ib having an eccentricpin Ma with more or less eccentricity readily interchanged therefor.

In addition to the action of the bellow assembly 63 upon the arm 53 asdescribed the arm 53 is also controlled through the connecting linkageI20, IZI, I26, I27 and I29 by the overspeed governor l 35. Thus upon thesupercharger I39 being driven at a speed in excess of a predeterminedrate the overspeed governor I35 driven thereby through the shaft I31will actuate the pin wt to the right as viewed in Figure 7 so as toactuate through. the aforenoted linkage the arm 53 in acounter-clockwise direction. Actuation of the arm 53 in the latterdirection will of course cause valve hi to be moved upward and servomotor vane it moved in a counterclockwise direction opening the wastegate Ho and decreasing the driving speed of the supercharger I39.

The arm 53 is also controlled through the linkage I20, I'2I, I26, and HIby the difierential control diaphragm I62 so that upon the pressure ofthe fluid medium within the chamber 55 decreasing to a value within apredetermined difierential above atmospheric pressure, the diaphragm I62will move the stem I52 to the left as viewedin Figures 2 and '7 causingactuation of the arm 53 in a clockwise direction through the linkagesI5I, I26, MI, and MI. Such actuation of the arm 53% will of course causemovement determined minimum diflerential above atmos pheric pressure anend portion I521! of the stem iti, as shown in Figure 2, contacts theinner surface of the cap I'II so as to limit the movement of thediaphragm I62 and stem I52 in the opposite direction.

Through this latter novel arrangement the controlled pressure ismaintained in excess of a predetermined minimum difierential value aboveatmospheric pressure. Thus, in case a pressure is selected throughoperation of the lever II which may be less than the surroundingatmospheric pressure it will be readily seen that unless such a minimumdider'ential control means were provided the supercharger would stoprunning, since the pressure of the atmosphere would satisfy therequirements of the control diaphragm ti. However, with the latter novelminimum 'diderential control the supercharger would be kept running inorder to maintain a minimum pressure in excess of atmospheric pressureso as to maintain sumcient'air flow for cooling portions of the turbinehit and bearings as previously explained. The latter operation isindicated diagrammatically in Figure 9.

in order to move the servo motor It to the full decrease position and toblock out of operation differential diaphragm iti and pressureresponsive diaphragm element ti when the selector arm III is within 5degrees of the full decrease position, there is further provided a,novel low boost lock-out link indicated in Figures 3 and 7 by thenumeral ill-t. One end of the link tilt is pivotally connected through abolt till, to one end of the link mid and link ti. The bolt 2M as shownin Figures 3' and "7 also connects the links M and ti.

The opposite end of the link 200 has formed therein a longitudinal slot203 in which is positioned a bolt iltil. The bolt. 2M pivotally connectsthe links til and it and the link 2011. There is thus provided a lowboost lock-out which is controlled by the slotted link ltd connectedacross the two bolts Ni and wt of the linkage ill and tI provided at theselector eccentric Eta.

Thus, when the selector arm II is in the lockout range, that is therange immediately preceding the full decrease pressure position in whichrange it is desirable for purposes of safety to have rranual control ofthe device in a pressure decreasing direction, the cross link 2M locksthe valve linkage M and M and prevents the minimum differentialdiaphragm IE2 or bellows 63 from controlling the servo valve BI. Indoing so, the lever Ill loaded by the resilient means or spring tilt atthe governor plunger I34 will be deflected from theplunger I34 by theaction of the link iti moving to the left in response to the diderentialpressure action upon'diaphragm I63, or upon action of the link I22moving to the right in response to a decrease in thepressureacting-within the chamber upon bellows 83, as the lever 53 willbe held from moving in a clockwise direction for increasing thecontrolled pressure due to the locking action of the link 2110 on thelink 48 and arm 52. Thus within the aforenoted boost lock-out range, theauxiliary supercharger is locked from operation for pur poses of safety,through operation of the arm II by the waste gate I2b being adjusted tothe full open position.

.Although the present invention is only describedand illustrated indetail for one embodiment thereof, it is to be expressly understood thatthe same is not limited thereto. Various changes maybe made in designand arrangenient of the parts illustrated, as will now be apparent tothose skilled in the art. For a deflnition of the limits of theinvention, referenceshould be had to the appended claims.

What is claimed is:

1. A control mechanism comprising, in combination, a first floatinglever, a pilot valve connected to one end of said first floating lever,a-

second floating lever having one end operably connected to the other endof the first floating lever, a rotary control member, an eccentric pintothe other end of said second floating lever,'

hydraulic motor means being operated by the pilot valve, a shaft drivenby said motor means, means pivotally supporting said first floatinglever at a point intermediate the opposite ends thereof. and a linkconnecting the other end of said second floating lever to the other endof said first floatinglever so as to lock said membrane from operativerelation with said pilot valve under predetermined operating conditions.

2. A control mechanism comprising, in combination, a floating lever,control means operably connected to one end of said floating lever, amembrane responsive to changes in an operating condition, means operablyconnecting said membrane to the other end of said floating lever, and alink connected between said control means and said membrane and acrosssaid floating lever for placing said membrane out of operating relationwith said control means under predetermined operating conditions.

3. A control mechanism comprising, in combination, a lever, a servomotorsystem operatively controlled by said lever, a pressure responsivemember operatively connected to said lever for controlling said system,means operatively con-' nected to said lever for manually controllingsaid system, and linkage means connected across said lever and operableat a predetermined value of said pressure to lock said pressureresponsive member from control of said system.

4. A control mechanism comprising, in combination, a lever, a servomotorsystem operatively controlled by said lever, a first pressure responsivemember operatively connected to said lever for controlling said system,a second differential pressure responsive member operatively connectedto saidlever for controlling said system, linkage means connected acrosssaid lever and operable at a predetermined value of said first pressureto-lock said second differential pressure responsive member from controlof said system.

5. A control mechanism comprising, in com- Ieiiieticn, to lever, aservomotov system opcmtiveiy controlled by said lever, c first pressurercspom sive member operatively connected to said lever for controllingsclcl. system, as second oiifieventle-l pa'essm'c responsive memberoperetively con.- nectecl to said lever for controlling said system,limzese mews connected across seici lever and: operable by action. oiseicl first pressure responsive member to lock. seioi members fromcontrol of said. sstem, end manually operable means connected to saidlever for controlling said system during locking action of sale.linkage.

A control mechanism comprising, in oo2...- most-ion, eservomotor system,means for centre-E servomotor system, c first floating lever, coollyoperable means connecting one enclof lever to sole; control means, alever having on end operetively cted; to the other enei of the firstfloating responsive means connected to f eating lever the cthez end.thereof, mhi'one responsive to changes in s. fisst fluid; messure,membrane opeietively connected soicl first fleeting lever at at pointintermediate the opposite ends of said first floating lever, s sscoiiomembrane responsive to the difierence l com the first fluid pressure ande, second fluid 554i cssca'c, said second membrane cgaerstivelyconice-steal to said second. lever at a point imtermesliate theQPIJQblt/E ends of said second lever, s, means connected across meansfor connecting said. first floatlevoz' to said. control means, linkagearranged to lock scicl prcssmc responsive wemcrenes speed responsivemeans from o,:oilin55 sezvomctcr system during fore cetesmineoloperating conditions.

l. P mechanism comprismg, cone 1 at a lever, aservomotor systemoperatively ccntrolleoi oy lever, e, first pressure respcw 3 s o system,a second presence receive :1 ember operativeiy coimectec. to forcomtirollL-g system, i kegs means across said lever and operable at acol value of said first pressure to loci:

scccno pressure responsive member from control of said. system, andresilient means for: i'zrmitting' seicl second, pressuse responsive mem6o move freely during the locking action of .-'on, a lever, e,servoinotor system operativemember operstiveiy connected to said leveefor coo-ironing system, means ogcemtively con sects to said lever formanually controlling and. linkage means connected across seici membraneseep loslve changes the 010" lids lever cml operable at c m-efietermmcsiveins of seicl pressure to loci: sclcl pressm'e rcscocslve member fscmcontrol oi sclcl system, cool so silicnt meczos for permitting sold p1"scum vesponsive member to move freely relative to mid lever during thelocking action of sold linkage.

A'controi mechanism comprising, combimtioo, c servomotcr system, meansfor con trolling seici sexvomotor system, a. first floating lever,connecting means for connec mg one end. of eeici iizst floating lever toselcl control means, a second floating lever having one end operativelyconnected to the other end of the first fleeting lever, spec-Llresponsive means, and. spring biased lever means connecting said speedresponsive mecca the other end of said. second floating" lever, e, festmembrane responsive to changes in s, first fluid pressure, said firstmembrane operatively connected to said floating lever at a point lntermeiate the opposite coals of said first floating lever, at second membmcex'espcmsive to the :lificrence between the first fluid pressure coolsecond fluid pressure, said second, membrane operetively connected tosaid. second. fleeting lever: at c. point intermediate the oppm sitesaid. second flee-ting lever, c. linlzcge mestos arranged to lock said;connecting nieces and said pressure z'esgcoosive membranes spec-clresponsive means from controlling sesvo motor: system duringpseciet/erminezi operetconditions, and said spring biased lever mewspermitting serial membrcnes to move freely during the otion of saidlinkage means.

ii. A control mechanism for aircraft eegiiie of the class including anintake system and exhaust system; comprising, in combination, contsolshaft for commotion e, pilots control lever, 1".- wer means foreffecting the pressm'e in one of systems of the engine, means forcoarsely cconeetmg said control shaft to seems, selici connecting meansincluding 3.99, lever, and. an. eccentric means directly o sold shaft tosaid. floating lever; most control coneecteri to said fleeting lever andarranged to coctrol soici newer means so as the pressul'e in said onesystem or? the engine at a select value, sold eccentric means arrangedto cheese such selected value upon siljcstment oi sold shaft, zrneansconoci'css seici float-mg lever and operable ur'm. variance of said,pressure to a predates value to loci; boost control out c3 opesetiveyelction with power means.

ccizti'ci .cr an aircraft superchs-vgei", comprising, combination, 2.-servosystem for co trolling the clriveo. speed of the so to normallyprovide clefi" selected fluid; p-z'essure, for cor" trolling said cyst2, a first float tmileel fluici was w .isst membrane coon. tively coun ofirst floating iever ct mint interim. N; e o,. posite ends of said.levev, second. mew/Jolene responsive to in. pressure hetwc" thecontrolled fluid pressure and the prev mg atmospheric pressure, eeio'lsecond. c opemtiveiy con-- meet-eel to second. floating: lever at apoint intomecllcte the opposite of acid second. lever for efiectlsis:control c; scrvc-= motor system upon a predetermined diflerentialbetween said controlled fluid pressure and the prevailing atmosphericpressure.

13. A control mechanism for an aircraft supercharger, comprising, incombination, a servomotor system for controlling the driven speed of thesupercharger so as to normally provide a preselected fluid pressure,means for'controlling said system, a first floating lever, said controlmeans connected to one end of said first floating lever, a secondfloating lever having one end operatively connected to the other end ofthe first floating lever, a membrane responsive to changes in thecontrolled fluid pressure, said membrane operatively connected to saidfirst floating lever at a point intermediate the opposite ends of saidfirst floating lever, means responsivemo the driven speed of saidsupercharger and operatively connected to said second floating lever atthe other end thereof for eiiecting control of said servomotor systemupon predetermined speed conditions, and another membrane responsive tothe difierence in pressure between the controlled fluid pressure and theprevailing atmospheric pressure and operably connected to said secondfloating lever at a point intermediate the opposite ends thereof.

14. A control mechanism for an aircraft supercharger, comprising, incombination, a servomotor system for controlling the driven speed of thesupercharger so as to normally provide a preselected fluid pressure,means for controlling said system, a first floating lever, said controlmeans connected to one end of said flrst floating lover, a secondfloating lever having one end operatively connected to the other end ofthe first floating lever, a speed responsive means operatively connectedto the other end of said second floating lever, a first membraneresponsive to changes in the controlled fluid pressure, said flrstmembrane operatively connected to said first floating lever at a pointintermediate said opposite ends of said lever, a second membraneresponsive to the diflerence in pressure between the controlled fluidpressure and the prevailing atmospheric pressure, said second membraneoperatively connected to the second floating lever at a pointintermediate the opposite ends of said second floating lever, wherebycontrol of said servomotor system may be eflected through operation oi.said speed responsive means and said pressure responsive membranes.

15. A control mechanism for an aircraft supercharger, comprising, incombination, a servomotor system for controlling the driven speed 01 thesupercharger so as to normally provide a preselected fluid pressure,means for controlling said system, a first floating lever operativelyconnected to said control means; a second floating lever operativelyconnected to the first floating lever; a membrane responsive to changesin the controlled fluid pressure, said membrane operatively connected tosaid first floating lever; means responsive to the driven speed of saidsupercharger and operatively connected to said second floating lever foreiiecting control of said servomotor system to prevent the speed of thesupercharger from exceeding a predetermined maximum value; and anothermembrane responsive to the diiierence in pressure between the controlledfluid pressure and the prevailing atmospheric pressure and operativelyconnected to said second floating lever for efiecting an overridingcontrol of said servomotor system to maintain the controlled fluidpressure in excess of atmospheric pressure by a predetermined value,said other membrane so arranged that said controlled fluid pressurenormally maintains said membrane in an inoperative relation, and saidmembrane efiecting said overriding control only when the differencebetween the controlled fluid pressure and the prevailing atmosphericpressure is less than said predetermined value.

16. In an internal combustion engine of the class including an intakesystem and an exhaust system, a supercharger operatively associated withsaid intake system, means for driving said supercharger, means forcontrolling the driven speed of said supercharger, motor means foroperating said control means, means for controlling operation of saidmotor means, first means responsive to the pressure in one system foroperating said motor control means so as to normally maintain apreselected pressure in said one system; the improvement comprising asecond overspeed responsive means driven by said driving means foroperating said motor control means in such a manner as to prevent saidsupercharger from being driven at a speed in excess of a predeterminedmaximum value, third means inde pendent of said first means andresponsive to the difference between the pressure in said one sys-,

tem and the pressure of the prevailing atmosphere for effecting anoverriding control of said motor control means only upon saiddifferential Pressure decreasing below a predetermined mini mum value soas to maintain a pressure in said one system in excess of atmosphericpressure, and floating lever means operatively interconnecting saidflrst, second and third means to said motor control means.

HOWARD A. ERSON.

HAROLD A. W.

REFERENCES CIT The following references are flle of this patent:

UNITED STATES PATENTS Bhoults May 15, 1945 of record in the

